La微掺杂对Bi_2Sr_2CaCu_2O_(8+δ)化合物结构及导电特性的影响  

Influence of La-doping on the Structural and Electrical Properties of Bi_2Sr_2CaCu_2O_(8+δ) Compounds

作　　者：张影[1] 李茂林[1] 杨华哲[1] 祁阳[1,2] 

机构地区：[1]东北大学理学院,辽宁沈阳110004 [2]东北大学材料各向异性与织构教育部重点实验室,辽宁沈阳110004

出　　处：《东北大学学报（自然科学版）》2008年第11期1601-1604,共4页Journal of Northeastern University(Natural Science)

基　　金：国家自然科学基金资助项目(50572013)

摘　　要：采用络合物型溶胶-凝胶法,通过对Bi2Sr2CaCu2O8＋δ（Bi2212）超导相进行Bi位La微量掺杂制备（Bi1-xLax）2Sr2CaCu2O8＋δ化合物粉体,研究了La替代部分Bi所引起的结构及导电特性变化，该粉体制备以可溶性无机盐为原料,乙二胺四乙酸（EDTA）为络合剂,La微掺杂x范围为0.01-0.09.利用TG-DTA曲线对化学反应过程进行分析,利用X射线衍射进行相分析,利用标准四引线法测试导电特性随温度的变化（R-T）。结果表明,该粉体相仍保持正交Bi2212结构,但a和b轴长度增加,c轴减少;随La微掺杂的量的增加,对Bi2212相的导电特性影响显著。The powdered （Bi1- x Lax）2Bi2Sr2CaCu2O8＋δ superconducting compound were prepared from Bi2212 （Bi2Sr2CaCu2O8＋δ） by sol-gel technique with trace La doped in Bi site. The changes in the structure and electrical conductivity clue to the La doped as substitute for part of Bi were investigated. The La-doped samples were prepared with metal nitrates as starting materials and ethylenediaminetetracetic acid （EDTA） as chelating agent, in which the range of La-doping content was from 0.01 to 0.09. Thermal analysis （TG-DTA） and X-ray diffraction were employed to investigate the chemical reaction process and structural changes of the samples. The resistance measurements were carried out with a conventional four-probe method. Structural analysis showed that the powdered phase remains orthorhombic Bi2212 structure though the crystal axes a and b lengthen and c shortens. And the electrical conductivity of Bi2212 phase changes obviously with increase in La content doped, as shown by the R-T curves.

关 键 词：Bi2212 溶胶-凝胶法 LA掺杂 结构变化 超导电性 

分 类 号：TB303[一般工业技术—材料科学与工程]